In the next fifteen years, lagging economies, ethnic affiliations, intense religious convictions, and youth bulges will align to create a “perfect storm,” creating conditions likely to spawn internal conflict. Many internal conflicts generate internal displacements and external refugee flows, destabilizing neighboring countries. Although the likelihood of great power conflict escalating into total war in the next fifteen years is lower than at any time in the past century, conflicts—such as over Taiwan or between India and Pakistan—could still erupt. Over the next fifteen years, a number of countries will continue to pursue their nuclear, chemical, and biological weapons programs and...